Ring for a wrapping apparatus and a method for manufacturing the same

ABSTRACT

A ring member ( 10 ) of reinforced plastic construction for a wrapping machine, said ring member comprising a box-shaped portion ( 15 ) having a plurality of reinforcing fibre layers so arranged that the fibre directions are varied so as to achieve a sufficient strength and flexural rigidity, and a core part ( 17 ) of cellular plastic. The walls ( 14 ) of the box-shaped portion may deviate from a vertical or horizontal plane, and the wall may be provided with one or more flanges ( 16 ) oriented in a direction outward from the ring member or toward the center of the ring member. The box-shaped portion is preferably made of carbon fibre and epoxy resin, and the core part inside the box-shaped portion is of foamed polyurethane plastic. Inside the reinforcing plastic layers of the box-shaped portion it is also possible to laminate a steel reinforcement ( 18 ), to which a wrapping film feed apparatus ( 20 ) and possibly support rollers are fastened.

SUBJECT OF THE INVENTION

The invention concerns a ring member of reinforced plastic constructionfor a wrapping machine, said ring member being rotatable and having amainly ring-shaped structure.

The invention is associated with a wrapping machine whose wrapping unitcomprises a rotatable wrapping ring member. The wrapping ring member hasthe shape of a circular ring and, usually supported by rollers, rotatesin the wrapping machine either in a horizontal plane or in a verticalplane, while the object to be wrapped is wrapped by means of a plasticfilm band roll rotating with the ring member.

BACKGROUND OF THE INVENTION

The wrapping ring member is usually made of a metallic material, butwrapping ring members of reinforced plastic construction are also used.A wrapping ring member of reinforced plastic construction is presentedin patent EP 0 747 287 A1. However, a reinforced plastic structure hasgenerally not proved to be strong enough to withstand the stressescaused by the roll of plastic film band rotating with the wrapping ring.It has been established that, especially as the rotational speedincreases, the reinforced plastic structure is bent, causing problems.On the other hand, if the wrapping ring member of reinforced plastic isimplemented as a very massive structure, then it will be difficult tomanufacture, so this is economically not sensible.

OBJECT OF THE INVENTION

The object of the present invention is to achieve a new type of wrappingring member of reinforced plastic, which does not have thedisadvantages, described above.

FEATURES CHARACTERISTIC OF THE APPARATUS OF THE INVENTION

The wrapping ring member of the invention for a wrapping machine ischaracterized in

that the ring member of reinforced plastic construction for a wrappingmachine comprises a box-shaped portion having a plurality of reinforcingfibre layers laminated in different directions upon a core part ofcellular plastic or equivalent material,

that the box-shaped portion of the ring member is provided with areinforcement laminated inside the reinforced plastic layers in thebox-shaped portion, said reinforcement being preferably made of steel,

and that the reinforcement is a ring of the same form with the ringmember or its length only equals part of the length of the ring member.

In cross-section, the box-shaped portion of the ring-shaped member maybe e.g. of a rectangular, polygonal or circular form. Other formsdifferent from these are also possible. The essential point is that theform and structure of the ring member are designed to achieve a lightand strong ring that is well able to withstand the centrifugal forcesgenerated by the rotating ring member and the plastic film feedapparatus moving together with it.

EMBODIMENTS OF THE APPARATUS OF THE INVENTION

A preferred embodiment of the apparatus of the invention ischaracterized in that at least one of the reinforced plastic walls ofthe box-shaped portion of the ring member is inclined at an angledeviating form a vertical or horizontal plans.

A second preferred embodiment of the apparatus of the invention ischaracterized in that the reinforced plastic wall of the box-shapedportion of the ring member which is in engagement with a support rollerand/or guide roller of the ring member is inclined at an angle ofpreferably 45° relative to the vertical plane.

A third preferred embodiment of the apparatus of the invention ischaracterized in that the reinforced plastic box-shaped portion of thering member comprises at least one flange for support and/or guiderollers, which Is made of the same reinforced plastic material.

A fourth preferred embodiment of the apparatus of the invention ischaracterized in that the flange of the ring member is preferablyoriented in a direction inward from the box-shaped portion toward thecentre of the ring member or in the opposite direction, outward from thering member. Yet the flange may also be oriented in any other directionthat gives the ring member advantageous strength properties. Thus, theflange may be oriented e.g. in an upward or downward slanting direction.

A fifth preferred embodiment of the apparatus of the invention ischaracterized in that the box-shaped portion of the ring membercomprises two or more flanges, which may either be all oriented in thesame direction, partially in different directions or they all may beoriented in different directions.

A sixth preferred embodiment of the apparatus of the invention ischaracterized in that the reinforcing fibres in the box-shaped portionand/or flanges of the ring member are preferably carbon fibres, thebinding agent binding the reinforcing fibres is preferably epoxy resin,and that the core part inside the box-shaped portion is preferably madeof foamed polyurethane plastic.

A seventh preferred embodiment of the apparatus of the invention ischaracterized in that it comprises at least one bolt going through thebox-shaped portion of the ring member and through the core part of it,by means of which bolt the feed apparatus for a plastic film band rollcan be connected to the ring member.

An eighth preferred embodiment of the apparatus of the invention ischaracterized in that it comprises at least one threaded sleeve orcup-like threaded part laminated inside the box-shaped portion of thering member, to which threaded sleeve or part the feed apparatus of theplastic film band roll is connected with bolts.

A ninth preferred embodiment of the apparatus of the invention ischaracterized in that the reinforcement inside the ring member isprovided with at least one threaded hole for the attachment of a feedapparatus for a plastic film band roll.

A tenth preferred embodiment of the apparatus of the invention ischaracterized in that it comprises one or more guide or support rollersconnected either directly or via an adapter element to the box-shapedportion or flange of the ring member.

METHOD OF THE INVENTION

The invention also relates to a method for the manufacture of a ringmember of reinforced plastic construction for a wrapping machine.

By prior-art manufacturing methods, it has not been possible to producesufficiently strong ring members of reinforced plastic construction fora wrapping machine. Prior-art ring member structures are massive butstill too flexible. The object of the present invention is to achieve amethod that does not have the above-mentioned disadvantages.

FEATURES CHARACTERISTIC OF THE METHOD OF THE INVENTION

The method of the Invention is characterized in

that the ring member of reinforced plastic construction for a wrappingmachine is formed to a ring-like enclosure by laminating severalreinforcing fibre layers in different directions upon a core partpreferably made of cellular plastic or equivalent material,

and that inside the reinforced plastic layers in the box-shaped portionis laminated a reinforcement, which is a ring of the same form with thering member or its length only equals part of the length of the ringmember, and being preferably made of steel.

A preferred embodiment of the method of the invention is characterizedin that the ring member of reinforced plastic construction ismanufactured by

laminating the box-shaped portion upon the core part of cellular plasticor equivalent material by laminating several reinforcing fibre layerswith varying fibre directions on top of each other, and

after that, pressing the core part and the box-shaped portion laminatedupon it against each other.

A second preferred embodiment of the method of the invention ischaracterized in that the ring member of reinforced plastic constructionis manufactured by pressing, after lamination of the reinforced plasticlayers of the box-shaped portion, the reinforced plastic layers onto thecore part by means of presses.

A third preferred embodiment of the method of the invention ischaracterized in that

a flange is formed in the box-shaped portion of reinforced plasticconstruction by laminating several reinforcing fibre layers withdifferent fibre directions upon a core part of cellular plastic orequivalent material and bending the edges of the layers over each otherto form a flange,

whereupon the reinforcing fibre layers of the box-shaped portion arepressed upon the core part and the edges of the reinforcing fibre layersforming the flange are pressed against each other.

A fourth preferred embodiment of the method of the invention ischaracterized in that the ring member of reinforced plastic constructionis manufactured by making the box-shaped portion and/or flanges bylaminating several layers of carbon fibres with epoxy resin on top ofeach other upon a core part of foamed polyurethane plastic.

A fifth preferred embodiment of the method of the invention ischaracterized in that the ring member of reinforced plastic constructionis manufactured by

first laminating the box-shaped portion by laminating severalreinforcing fibre layers with varying fibre directions on top of eachother,

and after that supplying foaming cellular plastic or equivalent materialinto the space inside the box-shaped portion.

EXAMPLES OF EMBODIMENTS

In the following, the invention will be described in detail by the aidof a few examples with reference to the attached drawings, wherein

LIST OF DRAWINGS

FIG. 1 presents a ring member for a wrapping machine in top view.

FIG. 2a presents a section through the ring member in FIG. 1, takenalong line II-II

FIG. 2b corresponds to FIG. 2a and presents a second embodiment of thering member.

FIG. 3 corresponds to FIG. 2 and presents a third embodiment of the ringmember.

FIG. 4 corresponds to FIG. 2 and presents a fourth embodiment of thering member.

FIG. 5 corresponds to FIG. 2 and presents a fifth embodiment of the ringmember.

FIG. 6 corresponds to FIG. 2 and presents a sixth embodiment of the ringmember.

FIG. 7 corresponds to FIG. 2 and presents a seventh embodiment of thering member.

FIG. 8 presents a cross-section of yet another embodiment of the ringmember.

DESCRIPTION OF THE DRAWINGS

FIG. 1 presents the circular ring member 10 of a wrapping machine in topview. The figures do not show the frame of the wrapping machine or anyother parts belonging to it. The rotating ring member 10 is usuallysuspended using a plurality of guide and support rollers mounted on theframe of the wrapping machine and engaging the ring member. For the sakeof clarity, FIG. 1 shows one support roller 11 stabilising the ringmember 10 from outside in a radial direction, and one support roller 12supporting the ring member from below. In reality, there are a pluralityof such rollers on different sides of the ring member 10.

FIG. 2a presents a cross-section of the ring member 10 in FIG. 1, withsupport rollers 11 stabilising the ring member 10 from outside in aradial direction and support rollers 12 supporting the ring member 10from below. As can be seen from FIG. 2a, the ring member 10 consists ofa box-shaped portion 15 and a horizontal flange 16 incorporated with it.Both the box-shaped portion 15 and the flange 16 comprise severalreinforcing fibre layers in which the fibres have been arranged in avarying manner in different directions in order to achieve a sufficientstrength and flexural rigidity. The reinforcing fibres are preferablye.g. carbon fibres and the binding agent used with them is epoxy resin.The box-shaped portion 15 is filled with a lighter yet sufficientlystrong filler 17, such as e.g. foamed polyurethane plastic.

It is also possible to implement the ring member 10 as in FIG 2 b sothat it has no flange 16 at all. In this case, the guide and supportrollers 11 and 12 engage the box-shaped portion 15 of the ring member 10directly from different sides of it. The suspension of the ring member10 can also be implemented In an inverse manner such that the guide andsupport rollers are fastened to the ring member 10 of the wrappingmachine, either directly or via adapter elements. In this case, therollers of the ring member 10 engage a second ring, which is notrotatable and is mounted on the frame of the wrapping machine. Thisembodiment is not presented in the drawings.

At the lower edge of the box-shaped portion 15 of the ring member 10there is additionally a reinforcement 18, preferably of steel, laminatedinside the reinforcing fibre layers. The reinforcement 18 may be a ring,but it may also only extend through part of the ring member 10. Thereinforcement 18 can be provided e.g. with holes 19 drilled from outsidethe ring member 10 and the holes can be provided with threads, thusallowing a feed apparatus for a plastic film band roll or some otherpiece of equipment to be fastened to the ring member 10.

FIG. 3 presents a second embodiment of the ring member 10 for a wrappingmachine, in which the box-shaped portion 15 of reinforced plastic onlycontains filler material 17 without a metallic reinforcement aspresented in FIG. 2. In this case, a feed apparatus 20 for a plasticfilm band roll or other device to be attached can be fastened e.g. withbolts 21 going through the enclosure 15.

In FIG. 4, the ring member 10 for a wrapping machine comprises one ormore threaded sleeves 22 laminated inside the box-shaped portion 15 ofreinforced plastic. In this case, the feed apparatus 20 for a plasticfilm band roll is attached to the ring member 10 with bolts 21 screwedinto the threaded sleeves 22.

In FIG. 5, the ring member 10 for a wrapping machine comprises one ormore threaded parts 23 laminated inside the box-shaped portion 15 ofreinforced plastic. In this case, the threaded part 23 only extends e.g.halfway through the box-shaped portion 15. The feed apparatus 20 for aplastic film band roll is attached to the ring member 10 with bolts 21screwed into the cup-like threaded parts 23.

FIG. 6 presents a cross-section of the ring member 10 in which the ringmember 10 consists of a box-shaped portion 15 and two horizontal flanges16 a and 16 b integrated with it. In this case, the support rollersengage the ring member 10 from outside, between the flanges 16 a and 16b. The support rollers under the ring member engage the lower surface ofthe lower flange 16 b. The box-shaped portion 15 and the flanges 16 aand 16 b have several reinforcing fibre layers, and filler material 17Is provided inside the box-shaped portion 15. The feed apparatus 20 fora plastic film band roll can be connected to this embodiment by any oneof the methods described above.

FIG. 7 presents a cross-section of a ring member 10 of reinforcedplastic for a wrapping machine in which one 14 of the walls of thebox-shaped portion 15 is in an oblique position. This wall 14 ispreferably at an angle of 45° to the horizontal and vertical planes. Inthis case, a support roller 11, also mounted at an angle of 45°,engaging this wall 14 replaces separate horizontal and vertical supportrollers The oblique wall 14 also has the effect of making the structureof the box-shaped portion 15 advantageously more rigid than arectangular box-shaped structure.

FIG. 8 illustrates an embodiment of the ring member 10 in which theflange 16 of the box-shaped portion 15 is oriented in a direction towardthe centre of the ring member 10. In this case, the support rollers ofthe ring member 16 can be placed on the interior side of the ringmember, whereas normally the flange 16 and support rollers are placed onthe outer side the ring member 16. As the centrifugal force tends tostretch the ring member 16 outwards when the ring member 16 is rotatingat a high speed, the load applied to the support rollers can be reducedby placing the rollers on the interior side.

ADDITIONAL REMARKS

It is obvious to the person skilled In the art that differentembodiments of the invention may vary within the scope of the claimspresented below.

What is claimed is:
 1. Ring member (10) of reinforced plasticconstruction for a wrapping machine, said ring member being of a mainlyring-shaped form and rotatable, characterized in that the ring member(10) of reinforced plastic construction for a wrapping machinecomprises, in cross section a box-shaped portion (15) having a pluralityof reinforcing fibre layers laminated in different directions upon acore part (17) of cellular plastic material, that the box-shaped portion(15) of the ring member (10) is provided with a reinforcement (18)laminated inside the reinforced plastic layers in the box-shapedportion, said reinforcement made of steel, and that the reinforcement(18) is a ring of the same form with the ring member (10) or its lengthonly equals part of the length of the ring member; means on said ringfor connecting a plastic film roll of said wrapping machine to saidring.
 2. Ring member (10) as defined in claim 1, characterized in thatat least one (14) of the reinforced plastic walls of the box-shapedportion (15) of the ring member (10) is in an inclined positiondeviating form a vertical or horizontal plane.
 3. Ring member (10) asdefined in claim 2, characterized in that the reinforced plastic wall(14) of the box-shaped portion (15) of the ring member (10) is inengagement with a support and/or guide roller (11) of the ring memberand is inclined at an angle of preferably 45° relative to the verticalplane.
 4. Ring member (10) as defined in claim 3, characterized in thatthe reinforced plastic box-shaped portion (15) of the ring member (10)comprises at least one flange (16) made of the same reinforced plasticmaterial for the support and/or guide rollers (12, 13).
 5. Ring member(10) as defined in claim 4, characterized in that the flange (16) of thering member (10) is preferably oriented in a direction from thebox-shaped portion (15) inward toward the centre of the ring member orin the opposite direction, outward from the ring member.
 6. Ring member(10) as defined in claim 1, characterized in that the box-shaped portion(15) of the ring member (10) comprises two or more flanges, which mayeither be all oriented in the same direction, partially in differentdirections or they all may be oriented in different directions.
 7. Ringmember (10) as defined in claim 1, characterized in that the reinforcingfibres in the box-shaped portion (15) and/or flanges of the ring mem-ber(10) are carbon fibres, the binding agent binding the reinforcing fibresis preferably epoxy resin, and that the core part (17) inside thebox-shaped portion is made of foamed polyurethane plastic.
 8. Ringmember (10) as defined in claim 1, characterized in that said correctingmeans comprises at least one bolt (21) going through the box-shapedportion (15) of the ring member (10) and its core part (17), by means ofwhich bolt the feed apparatus (20) of a plastic film band roll can beconnected to the ring member.
 9. Ring member (10) as defined in claim 1,characterized in that said correcting means comprises at least onethreaded sleeve (22) or cup-like threaded part (23) laminated inside thebox-shaped portion (15) of the ring member (10), to which threadedsleeve or part the feed apparatus (20) of a plastic film band roll isconnected with bolts (21).
 10. Ring member (10) as defined in claim 1,characterized in that the reinforcement (18) inside the ring member (10)is provided with at least one threaded hole (19) for the attachment of afeed apparatus (20) for a plastic film band roll.
 11. Ring member (10)as defined in claim 4, characterized in that said connecting meanscomprises one or more guide or support rollers connected either directlyor via an adapter element to the box-shaped portion (15) or flange (16)of the ring member (10).